Experts are urging the Bush administration to use patience and caution in its approach to Iran over its nuclear ambitions. The comments by former U.S. weapons inspector David Kay and others at an event on Capitol Hill Wednesday came as President Bush and other officials reiterated a call for Iran to end its uranium enrichment efforts and reach a peaceful and negotiated solution.

David Kay, who has been critical of the Bush administration's faulty pre-war intelligence on weapons of mass destruction in Iraq, says Washington needs to proceed cautiously because serious questions remain about its ability to assess realities on the ground in Iran.

While the government in Tehran has established what he calls "a substantial foundation" for a nuclear weapons program, Kay asserts any serious threat is at least five years and possibly 10 or more years away.

"Iran does not today, and in my judgment will not for some time, pose a nuclear threat to the United States or the state of the [Middle East] region," Kay said.

Assuming Iran's government has or does proceed with a weapons program, Kay says it will find the process long and expensive, presenting many negotiating opportunities.

However, Kay and others, citing media reports in recent months, worry that some officials in the Bush administration may be pressing for military action and regime change in Iran.

That would be a huge mistake, says Joseph Cirincione, another critic of the administration approach on Iran.

He asserts the impasse with North Korea, which now claims to have tested a nuclear weapon, underscores the need for a different course with regard to Iran.

"The longer you wait, the higher the price of a deal and the greater the risk that you won't get any deal at all," Cirincione said. "If they conclude, like the North Koreans concluded, that there is no bargaining with these people, there is no satisfying, and there is a faction in Iran that believes this, that the administration has decided to change the regime."

Cirincione asserts a heated debate is under way within the administration, between supporters and opponents of military action against Iran.

Sam Gardiner, a retired U.S. Air Force Colonel and instructor at the National War College, has stirred controversy by spelling out in some detail what he believes is administration contingency planning if a decision were made to go ahead with a military strike.

"The next step on the table is to escalate this not to a ground operation, but to an air strike, which would probably in its initial stages be five nights," he said. "In those five nights we will attack the known nuclear facilities. In addition to that we will attack some of the Iranian military capabilities."

Such a course, Gardiner predicts, would trigger numerous negative reactions, such as stepped up attacks on U.S. troops in Iraq, Iranian actions against shipping through the Strait of Hormuz, and Hezbollah action against Israel.

In response to recent media reports speculating about possible U.S. military action against Iran, U.S. officials have pointed out that contingency planning is routinely done at the Pentagon, but that no decisions regarding specific action against Iran have been made. In addition, President Bush, as recently as Wednesday, has emphasized that he intends to pursue a diplomatic approach to Iran's nuclear ambitions.

In any case, several of the experts who participated in a Capitol Hill panel discussion Wednesday say the president would have great difficulty selling any major military action against Iran to Congress.

Congressman Dennis Kucinich is a Democrat who organized the event.

"It would be the view of this member of Congress that this president would not have the ability to unilaterally order an attack, while we understand with the War Powers Act if he does order an attack anyway he still has to come back to Congress, but I think in this case given the gravity of it he would have to go to Congress first," he said.

Trita Parsi, president of the National Iranian American Council, says the U.S. needs to stop treating negotiations with Iran's government as, in his words, a concession or sign of weakness.

Military action, says Parsi, would merely result in the U.S. losing the battle for the hearts and minds of Iranians.

"If history is to repeat itself, as it so often does, then an attack on Iran would likely result in Iranians rallying around the flag, rather than people turning on their government as [former Iraqi dictator] Saddam thought they would," Parsi said. "The Iranian government would strengthen its hold on the country rather than be toppled."

Though President Bush has underscored the need for patient diplomacy regarding Iran, he adds that no option has been taken off the table.

In a news conference Wednesday, he said he continues to believe the U.S. needs to deal with Iran and North Korea "with more than one voice."

"The United States' message to North Korea and Iran and the people in both countries is that we have - we want to solve issues peacefully," Mr. Bush said. "We said there's a better way forward for you. Here's a chance, for example, to help your country economically. And all you got to do is verifiably show that you - in Iran's case, that you suspended your weapons program."

Iran vowed Wednesday to continue its nuclear program, which it says is intended for peaceful purposes, not weaponry. The U.S. and other permanent members of the U.N. Security Council are working to develop possible sanctions because of Tehran's defiance of calls to suspend its nuclear enrichment activities.